Preconditioning by isoflurane as a volatile anesthetic in elective coronary artery bypass surgery

BACKGROUND: Some pharmacological preconditioning approaches are utilized as an effective adjunct to myocardial protection, particularly following cardiac procedures. The current study addressed the potential clinical implications and protective effects of isoflurane as an anesthetic most applicable on postoperative myocardial function measured by cardiac biomarkers. METHODS: 46 patients were included in the study. In 23 of them, preconditioning was elicited after the onset of cardiopulmonary bypass via a 5-minute exposure to isoflurane (2.5 minimum alveolar concentration), followed by a 10-minute washout before aortic cross clamping and cardioplegic arrest. 23 case-matched control patients underwent an equivalent period (15 minutes) of pre-arrest isoflurane-free bypass. Outcome measurements included creatine phosphokinase (CPK) and creatine kinase&ndash;MB (CK-MB) levels until 24 hours after the surgery. RESULTS: None of the differences in enzyme levels at baseline and 24 hours after surgery between the two groups reached the threshold of statistical significance. The level of CPK was significantly reduced 24 hours after surgery compared with the baseline in the two groups. However, the postoperative release of CPK was consistently smaller in the isoflurane-preconditioned group than in the control group. The release of CK-MB displayed a statistically similar pattern. Multivariate linear regression analysis showed the effect of isoflurane regimen on reducing CPK level within the 24 hours after surgery compared with placebo. CONCLUSION: Our study supports the cardio protective effect of isoflurane and the role of pharmacological preconditioning of the human heart by this volatile anesthetic during elective coronary artery bypass surgery. &nbsp; Keywords: Preconditioning, Isoflurane, Volatile Anesthetic, Coronary Artery Bypass Surgery&nbsp; </p

Isolation improvement in UWB-MIMO antenna system using slotted stub

Multiple-input multiple-output (MIMO) scheme refers to the technology where more than one antenna is used for transmitting and receiving the information packets. It enhances the channel capacity without more power. The available space in the modern compact devices is limited and MIMO antenna elements need to be placed closely. The closely spaced antennas undergo an undesirable coupling, which deteriorates the antenna parameters. In this paper, an ultra wide-band (UWB) MIMO antenna system with an improved isolation is presented. The system has a wide bandwidth range from 2-13.7 GHz. The antenna elements are closely placed with an edge to edge distance of 3 mm. In addition to the UWB attribute of the system, the mutual coupling between the antennas is reduced by using slotted stub. The isolation is improved and is below -20 dB within the whole operating range. By introducing the decoupling network, the key performance parameters of the antenna are not affected. The system is designed on an inexpensive and easily available FR-4 substrate. To better understand the working of the proposed system, the equivalent circuit model is also presented. To model the proposed system accurately, different radiating modes and inter-mode coupling is considered and modeled. The EM model, circuit model, and the measured results are in good agreement. Different key performance parameters of the system and the antenna element such as envelope correlation coefficient (ECC), diversity gain, channel capcity loss (CCL) gain, radiation patterns, surface currents, and scattering parameters are presented. State-of-the-art comparison with the recent literature shows that the proposed antenna has minimal dimensions, a large bandwidth, an adequate gain value and a high isolation. It is worth noticeable that the proposed antenna has high isolation even the patches has low edge-to-edge gap (3 mm). Based on its good performance and compact dimensions, the proposed antenna is a suitable choice for high throughput compact UWB transceivers.Deanship of Scientific Research at Majmaah Universit

Removal of sulfur dioxide by carbon impregnated with triethylenediamine, using indigenously developed pilot scale setup

In order to provide protection against extremely toxic gases, activated carbon (AC) adsorption has long been regarded to be a useful technology in terms of gas removal. AC without chemical impregnation has been considerably less effective than impregnated ACs. AC in present use was modified with an organic amine, i.e., triethylenediamine (TEDA) to enhance the physical and chemical properties of AC in order to remove specific poisonous gases. With the rising concern on environmental pollution, there has been an increased curiosity in ACs as the means for eliminating pollutants from environment. Purpose of this study was to assess the TEDA impregnated AC in terms of adsorption capability for simulant gas like SO . Analysis was done in a properly designed setup. By using the scheme reported here, significant adsorption of toxic gas was obtained. Maximum removal capability observed by AC-4 for SO gas was 374 mg/g-C and its breakthrough time was 264 min. Breakthrough time and adsorption capacity of AC-4 was found to be 25 times and 10 times greater as compared to raw AC. Different characterization techniques were also used to study impregnated AC. It was found that chemical adsorption was the crucial means by which TEDA-impregnated AC removed the simulant gas. Langmuir model was best to represent equilibrium, and adsorption kinetics follow second-order model. The process was endothermic, favorable, and spontaneous

Infinity shell shaped mimo antenna array for mm-wave 5g applications

In this paper, a novel single layer Multiple Input–Multiple Output (MIMO) antenna for Fifth-Generation (5G) 28 GHz frequency band applications is proposed and investigated. The proposed MIMO antenna operates in the Ka-band, which is the most desirable frequency band for 5G mm-wave communication. The dielectric material is a Rogers-5880 with a relative permittivity, thickness and loss tangent of 2.2, 0.787 mm and 0.0009, respectively, in the proposed antenna design. The proposed MIMO configuration antenna element consists of triplet circular shaped rings surrounded by an infinity-shaped shell. The simulated gain achieved by the proposed design is 6.1 dBi, while the measured gain is 5.5 dBi. Furthermore, the measured and simulated antenna efficiency is 90% and 92%, respectively. One of the MIMO performance metrics—i.e., the Envelope Correlation Coefficient (ECC)—is also analyzed and found to be less than 0.16 for the entire operating bandwidth. The proposed MIMO design operates efficiently with a low ECC, better efficiency and a satisfactory gain, showing that the proposed design is a potential candidate for mm-wave communication.National Natural Science Foundation of Chin

Impregnation on activated carbon for removal of chemical warfare agents (CWAs) and radioactive content

Nuclear, biological, and chemical warfare (NBC) agents cause an inevitable threat to defense forces and civilians. Exposure to these toxic agents causes a lot of damage to lives. One can avoid the damage of these toxic agents by taking appropriate preventive measures. Respiratory protection is obviously necessary when military personnel or civilians get bounded by such type of noxious situation as contaminant-free air is then required for breathing and it can only be provided by means of a proper gas mask and relevant canister. In purification of contaminated atmospheres, activated carbon has so far met with outstanding success. It removes toxic chemicals either by chemical or physical adsorption from the contaminated air. When any toxic chemicals get adsorbed on the modified impregnated carbon's surface, they usually adsorb there by means of chemical reactions. Destruction of adsorbed toxic substances is expected by such a reactive carbon. In this perspective, an attempt has been made to review the literature from past decades on the removal of toxic chemical warfare agents (CWAs) and radioactive content from air stream in case of any nuclear, biological, and chemical attack by selectively modifying or impregnating the activated carbon surface. This review also covers some important adsorption properties of materials being used in gas mask filters for effective removal of chemicals from airstream. The probable removal mechanisms of various chemical warfare agents and radioactive content have also been reviewed

Multiple elements MIMO antenna system with broadband operation for 5th generation smart phones

In this work, a simple, low-cost, dual wideband sub6GHz Multiple Input Multiple Output (MIMO) antenna system for a smart phone is presented. The antenna system is fabricated using inexpensive and commercially easily available 0.8 mm thick FR4 substrate. The presented system consists of a single main board and two side boards containing eight antennas and feedings. The radiating elements are etched on the side boards to provide space for other electronic components and RF systems and sub systems. The dimensions of the main board and the two side boards are 150 x 75 x 0.8 mm(3) and 150 x 6 x 0.8 mm(3), respectively. The radiating elements are etched on the side substrates and the feeding network is designed on the main board. The proposed system resonates at 3.5 GHz and 5 GHz providing -10 dB bandwidth of 250 MHz (ranges from 3.3 GHz to 3.55 GHz) and 1700 MHz (ranges from 4.2 GHz to 6.2 GHz), respectively. The design and the arrangement of the structure enable pattern diversity and ensures at least -15 dB of isolation between any two given radiating elements. Moreover, various different key performance parameters such as envelope correlation coefficient (ECC), mean effective gain (MEG), channel capacity (CC), specific absorption rate (SAR), gain, and efficiency are also presented. It is found that the peak gain of the system is 5.8 dBi, ECC is lower than 0.015, efficiency ranges between 58% to 78%, peak SAR is 1.28 W/Kg, and the maximum CC is 40.2 bps/Hz within the frequency band of interest. In addition, to further demonstrate the usefulness of such structure as a smart mobile terminal, single and dual hand scenarios are also presented. To validate the concept and the computed results, a prototype is fabricated and measured. It is found that the simulated results are in very good agreement with the measured results. Based on the performance and the measured results, we believe that this structure holds a promising future within the next generation smart mobile phones.Universidad Carlos III de Madrid ; European Commissio

Synthesis and adsorption behavior of activated carbon impregnated with ASZM-TEDA for purification of contaminated air

In current study, ASZM-TEDA carbon (Carbon impregnated with Copper, Silver, Zinc, Molybdenum and Triethylenediamine) was successfully prepared with non-ammonium water soluble salts using incipient wetness method and TEDA was impregnated on raw activated carbon (RAC) by sublimation process. Aim of this study was to access the adsorption capability of RAC and ASZM-TEDA carbon for SO2 and NO2 gases. For characterization of material, XRD, SEM, EDX spectroscopy, EDX mapping, TGA, BET surface area analyzer and Boehm titrations were used. Results indicate that ASZM-TEDA carbon, prepared with non-ammonium salts, provided satisfactory protection against challenge gases. Using the FTIR based gas analyzer, a significant increase in breakthrough time of ASZM-TEDA carbon was observed i.e. 29.0% for SO2 and 18.7% for NO2 gases as compared to RAC and breakthrough time was 210 and 197 min, respectively. Adsorption capability of ASZM-TEDA carbon was found to be 390 mg NO2/g-C and 448 mg SO2/g-C. In comparison with RAC, ASZM-TEDA carbon showed enhanced adsorption capability up to 31.5% for NO2 and 55.9% for SO2. [Display omitted] •Non-ammonia water soluble salts were used for impregnation.•Metal oxides were impregnated on activated carbon by imbibing limit method.•Triethylenediamine was impregnated on metal impregnated activated carbon surface by sublimation process.•Prepared IACs were found promising and efficient for removal of SO2 and NO2 gases from air.•ASZM-TEDA carbon showed significant decontamination capability for SO2 and NO2 gases

High-Performance Multiple-Input Multiple-Output Antenna System For 5G Mobile Terminals

In this paper, the systematic design of a multiple antenna system for 5G smartphone operating at 3.5 GHz for multiple-input multiple-output (MIMO) operation in smartphones is proposed. The smartphone is preferred to be lightweight, thin, and attractive, and as a result metal casings have become popular. Using conventional antennas, such as a patch antenna, Inverted-F antennas, or monopole, in proximity to metal casing leads to decreasing its total efficiency and bandwidth. Therefore, a slot antenna embedded in the metal casing can be helpful, with good performance regarding bandwidth and total efficiency. The proposed multiple antenna system adopted the unit open-end slot antenna fed by Inverted-L microstrip with tuning stub. The measured S-parameters results agree fairly with the numerical results. It attains 200 MHz bandwidth at 3.5 GHz with ports isolation of (≤−13 dB) for any two antennas of the system. The influence of the customer’s hand for the proposed multiple antenna system is also considered, and the MIMO channel capacity is computed. The maximum achievable MIMO channel capacity based on the measured result is 31.25 bps/Hz and is about 2.7 times of 2 × 2 MIMO operati

V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications

Due to rapid growth in wireless communication technology, higher bandwidth requirement for advance telecommunication systems, capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired. In this paper, a compact Ultra-Wideband (UWB) V-shaped monopole antenna is presented. UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape. The proposed V-shaped is designed by incorporating a rectangle, and an inverted isosceles triangle using FR4 substrate. The size of the antenna is 25 mm×26 mm×1.6 mm. The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial, Scientific, and Medical (ISM), Worldwide Interoperability for Microwave Access (WiMAX), (IEEE 802.11/HIPERLAN band, 5G sub 6 GHz) which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission (FCC) with a maximum gain of 3.83 dB. The antenna is designed in Ansys HFSS. Results for key performance parameters of the antenna are presented. The measured results are in good agreement with the simulated results. Due to flat gain, uniform group delay, omni directional radiation pattern characteristics and well-matched impedance, the proposed antenna is suitable for WiMAX, ISM and heterogeneous wireless systems

Violence and abuse faced by junior physicians in the emergency department from patients and their caretakers: a nationwide study from Pakistan

Background: Across the globe, physicians in the emergency department (ED) are subject to violence by Patients and visitors. This has been shown to have negative effects on Patient care and physician performance. Study Objectives: This study was conducted to determine the magnitude of the problem in a developing country, to examine the effects of ED violence on physician satisfaction and performance, and to identify underlying etiologies and potential solutions. Methods And Setting: This nationwide cross-sectional study examined physicians-in-training (n = 675) in the EDs of nine major tertiary care hospitals in Pakistan. Results: The study reveals a significant problem, with 76.9% of physicians facing verbal (65.0%) or physical (11.9%) abuse from Patients or their caretakers in the previous 2 months. Male physicians were more likely than female physicians to be victims of such episodes (p \u3c 0.05), as were physicians who had spent more than 60 h in the ED in the past 2 months (p \u3c 0.0001). Reduced job satisfaction and a decline in the quality of job performance were reported by 40.7% and 44.3% of physicians, respectively. Junior trainee physicians were more likely to report impairment in job performance when compared to their senior colleagues (p = 0.014). Patients\u27 lack of education, overcrowding in the ED, and lack of coverage by security staff were identified as the major areas that need attention to address the problem. Conclusion: This study provides further evidence of the global prevalence of the problem, with the first nationwide epidemiological study performed in a developing country